def read_data():
    N, X = map(int, input().split())
    As = list(map(int, input().split()))
    return N, X, As


def solve(N, X, As):
    Bs = [(a, i) for i, a in enumerate(As)]
    Bs.sort()
    n_large = min(N, 20)
    n_small = N - n_large
    len_dp = sum(As[:n_small]) + 1
    dp_small = fill_dp(n_small, len_dp, Bs[:n_small])
    lst_large = brute_force(n_large, Bs[n_small:])
    for val, bits in lst_large:
        dif = X - val
        if dif == 0:
            return decode(bits, N)
        elif 0 < dif < len_dp and dp_small[dif]:
            return decode(bits + dp_small[dif], N)
    return "No"


def decode(bits, N):
    result = []
    for i in range(N):
        if bits & 1:
            result.append('o')
        else:
            result.append('x')
        bits >>= 1
    return ''.join(result)


def fill_dp(n, length, Bs):
    dp = [0] * length
    for val, idx in Bs:
        bit = 1 << idx
        for i in range(length - 1 - val, 0, -1):
            if dp[i]:
                dp[i + val] = dp[i] | bit
        dp[val] = bit
    return dp


def brute_force(n, Bs):
    lst = [(0, 0)] * (1 << n)
    length = 1
    for val, idx in Bs:
        bit = 1 << idx
        for i in range(length):
            v, mask = lst[i]
            lst[i + length] = (v + val, mask | bit)
        length <<= 1
    return lst


params = read_data()
print(solve(*params))